IX/40 The XMM-Newton 2nd Incremental Source Catalogue (2XMMi) (XMM-SSC, 2008)
The XMM-Newton 2nd Serendipitous Source Catalogue
XMM-Newton Survey Science Centre Consortium
<XMM-SSC, Leicester, UK (2008)>
=2008yCat.9040....0X 2008yCat.9040....0X
ADC_Keywords: X-ray sources ; Surveys ;
Mission_Name: XMM
Description:
The 2XMMi catalogue is the fourth publicly released XMM X-ray source
catalogue produced by the XMM Survey Science Centre (SSC) consortium,
following the 1XMM (Cat. IX/37, released in April 2003), 2XMMp (July
2006) and 2XMM (Cat. IX/39, August 2007) catalogues: 2XMMp was a
preliminary version of 2XMM. 2XMMi is an incremental version of the
2XMM catalogue.
The 2XMMi catalogue is about 17% larger than the 2XMM catalogue, which
it supersedes, due to the 1-year longer baseline of observations
included (it is about 8 times larger than the 1XMM catalogue). As
such, it is the largest X-ray source catalogue ever produced,
containing more than twice as many discrete sources as either the
ROSAT survey or pointed catalogues. 2XMMi complements deeper Chandra
and XMM-Newton small area surveys, probing a large sky area at the
flux limit where the bulk of the objects that contribute to the X-ray
background lie. The 2XMMi catalogue provides a rich resource for
generating large, well-defined samples for specific studies, utilizing
the fact that X-ray selection is a highly efficient (arguably the most
efficient) way of selecting certain types of object, notably active
galaxies (AGN), clusters of galaxies, interacting compact binaries and
active stellar coronae. The large sky area covered by the
serendipitous survey, or equivalently the large size of the catalogue,
also means that 2XMMi is a superb resource for exploring the variety
of the X-ray source population and identifying rare source types.
The production of the 2XMMi catalogue has been undertaken by the
XMM-Newton SSC consortium in fulfilment of one of its major
responsibilities within the XMM-Newton project. The catalogue
production process has been designed to exploit fully the capabilities
of the XMM-Newton EPIC cameras and to ensure the integrity and quality
of the resultant catalogue through rigorous screening of the data.
The predecessor 2XMM catalogue was made from a subset of public
observations emerging from a re-processing (in 2006/7) of all XMM
observations made prior to that point. The creation of the incremental
2XMMi catalogue has been driven by the desire to make public the
additional data from that re-processing that were proprietary at the
time of the 2XMM release but which subsequently became public before
01 May 2008. These have been augmented with a further 90 observations
that have been processed more recently as part of the routine,
day-to-day XMM data processing performed by the SSC, which were also
public at 01 May 2008. Together, these amount to 626 additional
observations (18%) with respect to 2XMM. With these new data, the sky
area covered grows by 19% while the number of detections increases by
17% and the number of unique sources by 15%. A key factor in the
decision to make the 2XMMi catalogue is the fact that, effectively,
all the new data have been processed with the same science analysis
software (SAS), pipeline and calibration as used in the aforementioned
re-processing. As such, the products from 2XMM and from the new
observations form a set of uniformly processed data. With software and
calibration changes now being propagated into the SSC processing
pipeline, it was deemed timely to make public the largest available
uniform catalogue.
The catalogue in its FITS version file (2xmmi.fit) has 246897 entries
made of 297 columns; a 'slim' version gathering the 39 most relevant
columns for the 191870 unique sources detected, is available as an
ascii table or a FITS binary table. In both versions, the columns are
fully described in the XMM-Newton User Guide available from:
http://xmmssc-www.star.le.ac.uk/Catalogue/UserGuide_xmmcat.html The
original names of these columns are included in the "Byte-by-byte
Description" below (uppercase names within parentheses)
Details about the construction of the catalogue can be found from the
XMM-Newton Survey Science Centre (http://xmmssc-www.star.le.ac.uk/)
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
xmm2is.dat 434 221012 The 2XMMi catalog, "slim" version
xmm2icat.fit 2880 137495 Full XMM-Newton 2nd Serendipitous Source Catalogue
(300 columns), FITS format
--------------------------------------------------------------------------------
See also:
http://xmmssc-www.star.le.ac.uk/Catalogue/2XMMi : 2XMM Home Page
B/xmm : XMM-Newton Observation Log (XMM-Newton Science Operation Center, 2002)
http://xmmssc-www.star.le.ac.uk/ : XMM-Newton Survey Science Centre,
University of Leicester
http://xmm.vilspa.esa.es/xsa/ : XSA Centre at ESA's XMM-Newton SOC
http://xcatdb.u-strasbg.fr/xcat-db/ : XCAT-DB at SSC institute, Strasbourg
http://ledas-www.star.le.ac.uk/ : LEDAS, at the SSC institute,
University of Leicester
J/A+A/493/339 : XMM-Newton serendipitous Survey V. (Watson+, 2009)
Byte-by-byte Description of file: xmm2is.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- Source [1,221170] (SRCID) Unique source index
8- 12 A5 --- --- [2XMMi ]
14- 29 A16 --- 2XMMi (IAUNAME) Unique source name (7)
31- 38 F8.4 deg RAdeg (SC_RA) Mean source right ascension (ICRS)
40- 47 F8.4 deg DEdeg (SC_DEC) Mean source declination (ICRS)
49- 52 F4.1 arcsec ePos (SC_POSERR) Mean error on position
54- 65 E12.6 mW/m2 Flux1 (SCEP1_FLUX) Mean flux in 0.2-0.5keV band
67- 75 E9.3 mW/m2 e_Flux1 (SCEP1FLUXERR) Mean error on Flux1
77- 88 E12.6 mW/m2 Flux2 (SCEP2_FLUX) Mean flux in 0.5-1.0keV band
90- 98 E9.3 mW/m2 e_Flux2 (SCEP2FLUXERR) Mean error on Flux2
100-111 E12.6 mW/m2 Flux3 (SCEP3_FLUX) Mean flux in 1.0-2.0keV band
113-121 E9.3 mW/m2 e_Flux3 (SCEP3FLUXERR) Mean error on Flux3
123-134 E12.6 mW/m2 Flux4 (SCEP4_FLUX) Mean flux in 2.0-4.5keV band
136-144 E9.3 mW/m2 e_Flux4 (SCEP4FLUXERR) Mean error on Flux4
146-157 E12.6 mW/m2 Flux5 (SCEP5_FLUX) Mean flux in 4.5-12keV band
159-167 E9.3 mW/m2 e_Flux5 (SCEP5FLUXERR) Mean error on Flux5
169-180 E12.6 mW/m2 Flux (SCEP8_FLUX) Mean flux in 0.2-12keV band
182-190 E9.3 mW/m2 e_Flux (SCEP8FLUXERR) Mean error on Flux
192-203 E12.6 mW/m2 Flux14 ? (SCEP9_FLUX) Mean flux in 0.5-4.5keV band
205-213 E9.3 mW/m2 e_Flux14 ? (SCEP9FLUXERR) Mean error on Flux14
215-221 F7.4 --- HR1 ? (SC_HR1) Hardness ratio of bands 1 and 2 (1)
223-229 F7.4 --- e_HR1 ? (SCHR1ERR) Mean error on HR1
231-237 F7.4 --- HR2 ? (SC_HR2) Hardness ratio of bands 2 and 3 (1)
239-245 F7.4 --- e_HR2 ? (SCHR2ERR) Mean error on HR2
247-253 F7.4 --- HR3 ? (SC_HR3) Hardness ratio of bands 3 and 4 (1)
255-261 F7.4 --- e_HR3 ? (SCHR3ERR) Mean error on HR3
263-269 F7.4 --- HR4 ? (SC_HR4) Hardness ratio of bands 4 and 5 (1)
271-277 F7.4 --- e_HR4 ? (SCHR4ERR) Mean error on HR4
279-287 E9.3 --- srcML (SCDETML) Source detection likelihood (2)
289-297 E9.3 --- extML (SCEXTML) Detection likelihood of the
extended source (3)
299-303 F5.3 --- Cst [0,1]? (SC_CHI2PROB) Constant probability (4)
305 I1 --- V [0,1] (SCVARFLAG) Variability flag (V=1)
307 I1 --- S [0,4] (SCSUMFLAG) summary flag (5)
309 I1 --- Chg [1,3] (SC_CHFLAG1) Changes compared to 2XMM (7)
311-312 I2 --- Nd (N_DETECTIONS) Number of detections
314-317 A4 --- --- [1XMM]
319-334 A16 --- 1XMM (MATCH_1XMM) Name of matched 1XMM source (6)
336-339 F4.1 arcsec o1XMM [0,3]? (SEP_1XMM) Distance of 1XMM source
341-434 A94 --- uLEDAS (LEDAS_URL) URL for details at LEDAS
--------------------------------------------------------------------------------
Note (1): The hardness ratio is defined as (F2-F1)/(F2+F1)
if F2 is the flux in the harder band (the hardness ratio is
therefore -1 for softest sources and +1 for hardest sources).
The energy bands are (note they differ from catalog 1XMM):
1 = 0.2 - 0.5 keV (narrow band)
2 = 0.5 - 1.0 keV (narrow band)
3 = 1.0 - 2.0 keV (narrow band)
4 = 2.0 - 4.5 keV (narrow band)
5 = 4.5 - 12.0 keV (narrow band)
6 = 0.2 - 2.0 keV = soft broad band, no images made
7 = 2.0 - 12.0 keV = hard broad band, no images made
8 = 0.2 - 12.0 keV = total band
9 = 0.5 - 4.5 keV = XID band
Note (2): defined as the maximum of the likelihoods of all detections
of this source.
Note (3): defined as the average of the extent likelihoods of all
detections of this source.
Note (4): χ2 probability that the unique source as detected by
any of the observations is constant, that is, the minimum value
of the EPIC probabilities in each detection.
Note (5):
The summary flag of the source is derived from the EPIC flag, and is
assigned the following values:
0 = good: none of the EPIC flags was set.
1 = source parameters may be affected: at least one of the EPIC
warning flags was set, but no possible-spurious detection flag
is set.
2 = possibly spurious source: at least one of the possible-spurious
detection flags was set but not the manual flag
3 = source located in a area where spurious detection may occur.
4 = source located in a area where spurious detection may occur and is
possibly spurious.
Note (6): within a radius of 3arcsec
Note (7): the 'Chg' flag indicates whether a source is (1) a 2XMM source
with unchanged averaged parameters, (2) a 2XMM source with changed
averaged parameters, or (3) a new source. In the case (3), the source
is named '2XMMi' followed by the contents of the 2XMM column (2nd
column); the name is otherwise 2XMM followed by the contents of the
2XMM column.
--------------------------------------------------------------------------------
Acknowledgements:
It is a pleasure to thank Clive Page and Simon R. Rosen,
who prepared the 'slim' version.
History:
* 03-Sep-2008: Original version
* 19-Jan-2009: energy bands in Note (1) above corrected (thanks to
Simon Richard Rosen)
(End) Francois Ochsenbein [CDS] 03-Sep-2008